Sudden Cardiac Arrest (SCA) is a sudden stop in effective blood circulation due to the failure of the heart to contract effectively or at all. Timely defibrillation is the single most important factor in saving an SCA victim's life. A treatment shock should be delivered within a few minutes after an event to be effective. Some studies show that an SCA victim's chance of survival drops 10 percent with each passing minute.
A Wearable Cardioverter Defibrillator (WCD or “wearable defibrillator”) may be worn by patients at risk of SCA. The WCD is generally lightweight and easy to wear, allowing patients to return to their activities of daily living, while having the peace of mind that they are protected from SCA. The WCD generally contains two main components—a garment and a monitor. The garment, worn under the clothing, detects arrhythmias and delivers treatment shocks. The monitor is generally worn around the waist or from a shoulder strap and records arrhythmias. The WCD continuously monitors the patient's heart and, if a life-threatening heart rhythm is detected, the device delivers a treatment shock to restore normal heart rhythm.
A WCD might be unready for use for a variety of reasons—the battery could be low, the battery could be disconnected, the electrodes could be disconnected or not ready for use, there could be a failure of a device self-test, etc. Accordingly, it is important that when a patient puts on a WCD that the device is ready for use. Existing WCDs use simple indicators to inform the patient of device readiness, but these can be obscure, confusing, and easy to ignore. An improved mechanism for reducing the likelihood that a WCD will be donned without being in a ready state has eluded those skilled in the art, until now.